Guitar Lab editor function sometimes cannot be used with G3n/G3Xn/B3n with firmware v2.1. (Due to this issue, distribution of the firmare v2.1 is currently suspended.)
When you experience this, please revert to the firmware v2.0 to avoid the problem.
We apologize for any inconvenience caused.
About Zoom North America:
Zoom North America is the U.S. affiliate of the Zoom Corporation (Japan). The company prides itself on offering its customers the very highest level of service and support.